Adjustable series shunt.



A, J. BROWN. ADJUSTABLE SERIES SHUNT. APIfLIoATIoN FILED FE11M, 1910.

Patented Got. 17, 1911t @muco/.zw @mM/KOM l 1. Q2@ a Q@ /Qv @5. @5m/uw UNITED sTATEs PATENT orsi-on.

f ARTHUR J. BROWN,

or MILWAUKEE, WISCONSIN, .assrenon To 'LLIs-cr-IALI/Inns COMPANY, A CORPORATION 0F NEW JERSEY. l,

`.amusfrannn snnrns sHUNT.

Specification of Letters Patent.

Patented 00u17, l191i.

Appuanon and February 14, 1910. serial No. 543,863.

silver (sometimes copper) connected across' the terminals of the series field winding, to

shunt a part of the armature current around the series windingfor the purpose of obtaining a proper compounding effect. U sually in such machines, it is difficult to provide the field magnets with exactly the proper number of series turns. In y large machines, designed for heavy current loads, it is generally impossible to do so for the yreason that very few series turns are necessary. In'fact'to obtain the proper series ampere turns with the full load current, l:frequently fractions of turns willv be required, It is therefore customary to provide a' greater number of series turns than would be required ifthe full load current traversed the seriesl winding and to rovide a shunt across the series fiel terminals whereby a art of the current 1s shunted around tain the 'proper ampere turns. The shunt referred to is usually non-inductive, and as commonly constructed, consists of a strip of German silver wound back and forth around porcelain tubes mounted in two parallel plates of insulation. The strip is thin and wide to obtain the proper resistance and heat radiating effects.

The above type of shunt is adjustable. It is therefore not necessary to carry in stock a large number of shunts of dierent sizes and capacit-ies in order that the proper compoundin effect may be obtained for each indivi ual machine. In .some of the earlier series-shunt constructions if the resistance of a particular shunt was too-great,

rt-ions of this resistance material were sheared off until Athe proper resistance was unnecessarily obtained. In this' event an large shunt frame was used. This was objectionabie forvthe reason that the'shunt 'is usually. attached to the the latter may be Increased of. they framel through the series winding to obframe of the-machine. w

The object of my invention is to provide a shunt, the frame ofv whichcan be ad .justed for any desired length of resistance .y

-materia-l, and to provide means whereby the effective resistance of the shunt in the frame may be materially altered.

In carrying out my invention, I mount .the strip'of resistance material in a sectional; frame,`whereby the length of the sides-of or decreased at will for any length of'resist'ance material, and provide the resistance material with anadjustable member so j that sa'id'-V member f may vary the effect of Ithe'resistance.v

More specifically considered, my invention consists in a series shunt having a zigzag or looped resistance metal, a substantially rectangular frame for the strip comprising four'meta-l castings for thecorners which castings pass two pairs of longitudinal parallel bolts each pair of which pass through opposite ends of the same corner castings, insulating blocks mounted on eachof the bolts, insulated rods mounted in lthefblocks, said rods being in two opposite parallel sets, said resistance strip being looped about the a plurality of insulated rods, end-bolts passing `through the metal castinffs at right angles to the aforesaid end-bol s for spreadingapart'the two pairs of longitudinal bolts andv blocks supported thereon, toy put the resistancel strip under tension, and a memberjformai terially altering the effect-ive resistance mov-A .ably mounted n said resistance material.

Referring t Vthe accompanying ysheet of drawings, Fig is anelevation of my shunt. Fig. 2 is a p tion, of the sameandf of the same. 4

A long flexible strip 10 ofl resistance 'material, preferably German silver, 'is zigzagged or wo-und back and forth' as shown so that the shunt -will be compactjThis stripis thin and wide so that the resistance will be high and the heat radiation sufcient to prevent an undesirable rise of tempera ture. f 'f The supporting frame is rectangular in shape, and n consists of four similar `cast metal. corner pieces 11, mounted" on lfour long longitudinal bolts 12, "and four -short Fig. 3 is an end view -`an view partlyin sec- By means of these Y minals (not shown) ceive the bolts, the

transverse bolts 13. As is clear from. the drawings, each cast metal corner piece is provided with two pairs of openings to'reholes of one pair being arrangedat right angles to the holes of the other pair. Each cast metal crner piece 11 isprovided with a perforated lug 14 by means of which the shunt may be attached to a support. v y

Mounted on each bolt 12 are a number of blocks 15 preferably of insulating material, such as fiber. The blocks 15 ,are arranged side by side and there is an equal number on each bolt. Each block .15 has a hole or opening-to receive th'e supporting bolt 12, and an opening arranged at right angles to the first opening to receive an insulated rod 16 o n which one section or loop of resistance strip 10 is supported. I have, in thise case, shown seven fiber blocks on each bolt. Each of the rods 16, about which the resistance material 10 is looped, is mounted in two opposite insulating supporting blocks 15, and is held in place by a nut 16a.I As is clear from the drawings, the rods are all parallel to each other andare arranged in two sets, the sets being in parallel planes. Mounted on each rod is a tube of insulating material 17, preferably of porcelain. These tubes are of equal length, and hold the inner ends of the Each pair of insulating blocks 15 andthe insulating rods 16 mounted therein, may be mounted on or removed from the bolts 12 as a unit, and therefore constitute one section of the frame.' The resistance strip 10 is wrapped back and forth around all vof the tubes and each free end is fastened to the,

last adjacent vsection or portion extending between two tubes by means of a clamp 18. clamps the ends of the be connected to the terof the series field winding. The longitudinal bolts are provided at bot-h ends with tightening nuts 19, by means of which, the fiber blocks can be held closely together. The shorter bolts 13 are each provided with four nuts 20, located on both sides of the corner of these nuts 20, and particularly the nuts on the inner side of the corner members, the two sets of longitudinal bolts 12, which carry the insulating blocks 15 and rods 16, can be spread apart so as to tighten or put tension in the loops of the resistance strips 10.

resistance strip can As is shown atl 21, the longitudinal bolts extend at one end of the shunt, beyond the corner members 11. The object of this is to permit the size of the frame to be increased without changing the bolts 12. If the resistance of the strip 10 is not sufficient, the nuts 19 and20 can be loosened and another set of insulating blocks 15 and supporting rods 16 canbe added and the frame will material.

blocks the proper distance apart.'

members 11. By means l museos then support a longer resistance strip, On the other hand, the size of the removing a suitable number of supporting blocks'or rods. But a better arrangement than this is obtained by employing a member 22 which is mounted upon and engages adjacent portions of the zigzag resistance This member 22, which includes three flat pieces engaging the full width of t-he strip, .is mounted slidably on the resistance strip and may be slid along lengthwise of the same. I/Vhen the proper amount of resistance is obtained the member or clamp' 22 may be tightened to the resistance strip .by means `of screws'23 which pass through the member 22. This member 22 which provides for varying the effective resistance of the series shunt may be taken from any 'two adjacent resistance turns and placed at if the resistance is too high, frame can be reduced by can bet accurately and definitely varied with very great precision by means of the adjustable member 22.

It is seen that my improved shunt is simple in construction and compact. As the frame consists of ai plurality of sections its size can be easily and quickly adjusted by .increasing or decreasing the number of sections. It will only be necessary tol carry in stock a few bolts of different sizes for shunts which will produce the proper compounding effect for machines of different sizes and conditions of windings. The real improvement of my invention consists in the provision of the member 22 which is mounted on the resistance strip for varying the e'ective resistance of the same. 4The arrangement requires no more room than if it were not present and is of considerable value.

It is evident that there may bemany modifications of the precise form and arrangement herein shown and described, and I aim in my claims to cover all such modifications .which do not involve a departure from the spirit and scope of'my invention.

What I claim as new is:

machine, a frame, astrip of resistance material mounted in said frame, a member adjustably mounted on said strip of resistance material for varying the effective resistance thereof, and another member engaging said adjustable memberfor clamping it in any desired position.

2. In a series-shunt for a dynamo-electric machine, a frame, a strip of resistance material wound back and forth in said frame forming loops, and adjust-able clamping means for short-circuiting one of said loops.

3. In combination, a frame, a zig-.zag resistancefmember supported` b said frame, and clamping means mounte on andsupported by said, resistance member to shortcirouitk certain portions thereof. l

4. In combination, a frame, a strip of resistance material Wound back and forth in said frame forming individually supported loops, and adjustable means supported by slaid strip Jfor short-eireuiting one of said oops. Y

5. In combination, a frame, a zig-Zag resistance strip supported by said frame, and

clamping means mounted on said resistance strip to short-circuit of, said means including a plurality of flat pieces engaging the full Width of 'said re'- sistanee strip.

In testimony whereof I-ax my signature, in the presence of two witnesses.

.ARTHUR J. BROWN.

Witnesses:

CHAs. L BromA ROB. E. STALL.

certain portions there 

